Pregnancy-Associated Myocardial Infarction in Alberta

Background: Cardiac disease is the leading cause of maternal mortality in developed countries, and myocardial infarction (MI) is an important cause of pregnancy-associated morbidity and mortality. These infrequent, but very serious, events are not optimally described in the medical literature. Objectives: This study describes a 15-year consecutive, retrospective cohort of confirmed pregnancy-associated MIs (PAMIs) identified in Alberta, Canada (2003-2017). Methods: Utilizing a provincial administrative database, a cohort of women with PAMI were identified using a validated algorithm. Additional cases were identified by reviewing provincial maternal mortality records. Medical record review was conducted on each case with further details obtained via linkage with a provincial coronary heart disease registry. Available angiographic images were also reviewed. Results: Forty-three cases of PAMI were identified in Alberta between 2003 and 2017, providing a crude incidence of ∼5.64/100,000 births. Rates of PAMI increased over the study period. Of the identified MIs, 16.3% occurred antepartum (mean gestational age of 18 weeks), while 30.2% were peripartum and 53.4% occurred within 6 months postpartum (at a mean of 7.8 weeks after delivery). The most common mechanism of PAMI was spontaneous coronary artery dissection (44.2%) and this mechanism predominated postpartum. Coronary artery disease was a frequent antepartum cause of MI, whereas demand ischemia was the leading cause of peripartum MI. Maternal mortality was approximately 9%. Conclusions: PAMI is an increasing cause of maternal morbidity and mortality in Alberta. Clinicians should have a high index of suspicion for PAMI and ensure optimal management of this dangerous complication of pregnancy.